Multicollinearity in Simple Terms
We all know the definition of multi-collinearity i.e. when 2 or more explanatory variable in multi regression model are highly linearly related then it’s called multicollinearity
Age and Selling price of a Car
Education and Annual Income
Height and Weight
Why should we remove multicollinearity from our model?
Example, You are watching WWE and Batista is thrashing Undertaker. Now you know that Batista is better.
But suppose it’s a Royal Rumble where 5 wrestlers are beating Undertaker simultaneously. Now, you can’t say which one is attacking with what intensity and thus you can’t say which wrestler among the five are better.
Thus when you have multiple variables which are correlated, the model is unable to give proper weightage about the impact of each variable. So, we need to remove redundant variables
What all methods are used to remove multi-collinearity?
There are two methods to do the same:-
1. VIF – It stands for Variance Inflation Factor. During regression analysis, VIF assesses whether factors are correlated to each other (multicollinearity), which could affect p-values and the model isn’t going to be as reliable
Factor with high VIF should be removed. A VIF of 1 suggests no correlation
2. PCA – Principal component analysis (PCA) is a technique used to emphasise variation and bring out strong patterns in a dataset. It’s often used to make data easy to explore and visualise.
How so we deal with Multicollinearity in our model?
1. You can use feature engineering to convert the two variables into one and then use this variable
2. Use VIF/PCA to eliminate one of the variables
You should eliminate the one which is not strongly correlated with the target variable
I think this is much about Multi-collinearity. Let me know if you have any questions
Keep Learning 🙂
The Data Monk